The concessionaire L&T Metro Rail Hyderabad (L&TMRH) has pressed into service as many as 10 launch girders across two of the three corridors at various work sites where the elevated metro rail is being built.
The box-type launch girders are about 34 metres in length and weigh about 300 tonnes.
They are first made in the casting yard before being dismantled and brought to the identified work site after dark on huge trailers. The parts of the girders are lifted with the help of hydraulic cranes of 150 tonnes each atop two piers or pillars and refitted. These launch girders would place the readily manufactured segments. Each segment has unique specifications and is numbered accordingly.
These are placed one beside the other, strung, glued and steel cabled tight to form the superstructure or the viaduct over which the rails are placed, senior metro rail officials explain.
While three-fourths of the metro rail corridors would have single piers, there are also ‘U’ shaped, hammer headed and other shaped piers depending on the topography of the viaduct or for special reasons as in forming ‘looplines’ also known as pocket tracks.
These looplines are akin to those ground-based rail system have where any train, in case of a breakdown or emergency, is moved away from the main line at frequent intervals so as not to disturb the regular traffic. Metro rail authorities have decided on three such looplines – at Begumpet near the HPS School, between S.R. Nagar and Ameerpet and Bhoiguda.
Hyderabad Metro Rail Managing Director N.V.S. Reddy informed that these looplines would be built to an extent of 200 metres slightly away from the main line so as to move a train on to it in case of a technical glitch or during an emergency and not disrupt the other services. A six-car train would be occupying 30 metres length so it is sufficient. While track laying work is expected to start anytime soon on the Nagole-Mettuguda stretch, viaduct and piers work is on between Miyapur-Ameerpet, piers and foundations work is on from L.B. Nagar to Moosarambagh, Hitec City to Jubilee Hills check-post, etc.
